Could PD-L1 positivity be associated with venous thrombosis in patients with non-small cell lung cancer?

The risk of venous thromboembolism (VTE) is increased in non-small cell lung cancer (NSCLC), and defining at-risk patients is important. Thus, we aimed to assess the association between programmed cell death ligand 1 (PD-L1) expression and VTE [pulmonary embolism (PE), deep venous thrombosis (DVT)] in NSCLC. In this retrospective, observational multicentre study, 369 patients with NSCLC who had PD-L1 immunohistochemistry based on biopsies taken between January 2017 and December 2019, were divided as PD-L1-positive ( n = 181) and -negative ( n = 188) groups, and low-positive ( n = 99) and high-positive ( n = 82) PD-L1 groups. Among all population, 12.5% of them developed a VTE during a median follow-up of 474 days. The rates of DVT, PE, and PE + DVT were 5.7%, 6% and 0.8%, respectively. VTE (15.5% vs. 9.5%) and DVT (3.8% vs. 7.4%) were similar between two groups, while PE was significantly higher in PD‑L1-positive group than those in PD-L1-negative group (11.1% vs 1%, p